<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Document</title>
</head>
<body>

  <script>

    var a = Symbol('a');

    var obj = {
      [a]:1,
      b:2,
      c:3
    }

    obj.a = 4;
    console.log(obj.a);
    console.log(obj[a]);

    // 新增了一个属性名独一无二的数据
    var b = Symbol('b');
    obj[b] = '后盾人';



  </script>


</body>
</html>
